Philly mapped street trees for smarter maintenance

Philadelphia has hundreds of thousands of trees, but it has never had a comprehensive inventory of its street trees—until now.

Philadelphia Parks and Recreation now has a complete digital record of the city’s street trees, achieved by using a custom-capture street view tool developed by the technology company CycloMedia, part of a one-year long pilot of the software by the City.

CycloMedia’s tool is “like Google Maps on steroids,” said Parks and Rec’s lead GIS Specialist Nora Dougherty, who spearheaded the project. It is a way of capturing all kinds of high-definition imagery that is geolocated, which means it can be used for a variety of projects. The tool is easy enough for non-experts to use, according to Mark Wheeler, Chief Geographic Information Officer for the Office of Innovation and Technology, plus the custom-captured imagery can be fully integrated with the city’s existing GIS software. CycloMedia’s tool captures an unprecedented level of detail in the images it records: You’re able to see features like address numbers and even deterioration of rooflines. Plus, every image is date and time stamped, so the user can verify that the images are consistent. This tool is also highly accurate for measuring distances and heights.

After all the streets in Philadelphia were captured using the technology, GIS technicians Tom McKeon and Stuart Olshevski virtually traveled down every street and dropped pins marking the location of each tree. The result is an inventory of nearly 112,000 street trees with geolocation data, which means street trees are now represented in a new layer of geographic information that can be mapped and analyzed. (Forest trees make up the other thousands of trees in Philadelphia, but it’s nearly impossible to accurately inventory them.) Information about the health and species of street trees is also being recorded. 

“We believe we’re the first city to do a street tree inventory like this,” Dougherty said. “Most cities hire a consulting firm to get boots on the ground, but using this approach, we saved several thousands of dollars.”

That savings has lasting value too, as the city will be better able to use the inventory to monitor hazardous trees to prevent accidents, look at trends (such as why certain species of trees might be dying), and see which neighborhoods have more or less access to tree cover. That strategic approach will help inform where the city directs its resources when it comes to tree planting and maintenance.

The street tree inventory will be available on August 5 on Open Data Philly, and in an interactive map will be on the city’s website. Citizens can use that information to create their own maps and take action to monitor the trees in their neighborhood. The inventory will be useful to citizens who can report occurrences—like falling trees—during a weather event, as well as to stewardship groups like the neighborhood Tree Tenders trained by the Pennsylvania Horticultural Society.

“Through inventorying, [Parks and Rec] were able to identify areas where they would like to plant more street trees to increase the city’s goal of having a 30 percent tree canopy,” said Wheeler, referring to the target set in the city’s sustainability plan. Parks and Rec can better target plantings by making sure the trees are the appropriate species for the area and by considering in advance potential obstacles, such as overhead wires, driveways, or fire hydrants.

More detailed information such as the species, health status, and size of each tree in the inventory is expected to be publicly available in August of 2017, after certified arborists look at each tree and collect information.

“An inventory of trees, being that trees are live entities, is a live database. What you see today might not be what you see a month from now,” said Parks and Rec’s Special Project Manager, John Piller. “Having the inventory helps us be proactive in addressing the concerns of the city, citizens, and Council.” It will be important to continuously update the inventory to reflect fallen trees, new trees, and pruning so that the data stays accurate as nature fluctuates.

In addition to its work on the street tree inventory, Parks and Rec is getting ready to implement Cityworks, a digital system to manage urban forestry. Cityworks will incorporate the data from the tree inventory and will allow the Department to better respond to requests. The current asset management system is largely paper-based, but the new integrated system will be more efficient as it can receive work orders and deploy staff to look at trees. These staff will be better prepared and organized to go out into the field, as they’ll already have data on the trees in question before they arrive.

Beyond Parks and Recreation, other city offices have found many advantages to employing the CycloMedia technology. According to Wheeler, the tool has shown an incredibly fast adoption rate in city government: Within four months of the pilot’s beginning, there were about 360 separate accounts using the tool, proving the tool’s wide applications of use. Licenses and Inspections can use it for pre- and post-inspection work, and they can use it to monitor building vacancy by validating their statistical model of vacancy likelihood, as they are able to see boarded up or broken windows; the Law Department can verify vacant properties for sheriff sales; the Water Department can start planning for green infrastructure like rain gardens by taking measurements of sidewalks and street width and mocking up plans; and the Streets Department can spot, evaluate, and measure street signs and poles (with the potential to make an inventory of them in the future).

Wheeler is quick to point out that this tool does not obviate the need for real engineering. “This tool is for preplanning and assessment—assessing the conditions, the area, and the possibilities,” he said. As the city’s CycloMedia pilot ends on July 30, Wheeler is at work to see how to keep tool in the city’s portfolio in the future so that city offices can retain their access to updated images and can continue to develop these innovative projects.